Fuse



Nov. 14, 1933. T. BIRKENMAIER FUSE 2 Sheets-Sheet 1 Filed Nov. 16, 1931 3. Plv F Nov. 14, 1933. T. BIRKENMAIER FUSE Filed Nov. 16, 1951 2 Sheets-Sheet 2 Patented Nov. 14, 1933 PATENT OFFICE FUSE Theodore Birkenmaier,

St. Louis, Mo., assig'nor to W. N. Matthews Corporation, St. Louis, Mo., a corporation of Missouri Application November 16, 1931 Serial No. 575,193

10 Claims.

This invention relates to fuses, and with regard to certain more specific features, to throw-out fuses.

Among the several objects of the invention may be noted the provision of a throw-out fuse which isadapted positively to pull at least a portion of a fuse link from a cartridge upon blowing thereof, and completely to disengage said portion from the cartridge; the provision of means of the class described which may readily be attached to most of the cartridges now available; the provision of separate means adapted for use with fuses and cartridges of common construction which is simple in construction and operation. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which Will be indicated in the following claims.

In the accompanying drawings, in which are illustrated several of various possible embodiments of the invention,

Fig. 1 is a side elevation of a characteristic cartridge including the throw-out means of the present invention, the unbroken fuse element being shown in position;

Fig. 2 is a vertical section of the cartridge, etc., shown in Fig. 1, with the elements in their position at the instant the fuse link blows;

Fig. 3 is a bottom plan view of an expelling means shown in Fig. 1;

Fig. 4 is a section taken substantially on line 4 4 of Fig. 3;

Fig. 5 is a side elevation similar to Fig. l illustrating a modification of the invention, the fuse link being in unbroken condition;

Fig. 6 is a vertical section similar 'to Fig. 2, and illustrating the elements ofthe Fig. 5 modication in their position at the instant the iuse blows; and,

Fig. 'I is a section taken substantially along line 7-7 of Fig. 6.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Broadly speaking, it has been shown to be decidedly advantageous to provide means, either in a fuse link or in the cartridge enclosing the fuse link, to separate, instantaneously, the two pieces of a broken fuse element immediately upon blowout thereof. The advantage accrues in the fact that arcing, sparking, and the like are positive- 1y and instantaneously inhibited. However, most of the prior devices constructed with such forcible expulsion means have been disadvantageous in that the lower or expelled portion of the fuse link, being directly connected to the connecting means of a cartridge, has, upon blow-out been permitted to dangle freely from the end of the cartridge in such position as to strike lower wires in a line installation or the like, thereby incurring the serious disadvantage of short circuiting. Further, the lower end of the fuse link is ordinarily connected to an exposed connecting post on the cartridge, and, on account of corrosive action of the atmosphere, the connection has frequently become corroded to the extent that replacement with a new fuse link is quite difficult.

The present invention, recognizing the above diiculties, provides a means whereby all of the desired forcible expulsion advantages may be retained with the additional advantage, however, that the lower portion of the fuse link upon expulsion is completely disengaged from the cartridge and allowed to iall freely, thereby minimizing danger from shorts and the like and leaving the cartridge in condition for immediate replacement with a new fuse link.

Referring now more particularly to Fig. l, there is illustrated at number-al l the customary insulating material tube of a line-installation fuse cartridge. Numeral 3 indicates the upper' connecting block of such cartridge, having a stud 5 adapted to clamp one end 7 of a fuse link 9 against a clamping surface 1l (see also Fig. 2). The fuse link 9 includes a fusible portion 13 so proportioned as to blow out or rupture upon the passage of current in excess of a predetermined value. The fuse link 9 also includes a relatively long, relatively non-fusible connecting pig-tail or wire 15, which is preferably made of bendable material such as stranded copper wire or the like iiexible material.

Numeral 1'? indicates the lower connecting block of the fuse cartridge assembly. The lower block i7 is provided with a stud 19, to which, in prior methods of using the cartridge, the lower end of the connecting wire 15 was secured.

Numeral 2l indicates broadly an expulsion means comprising a strip of spring material, such as brass, which is also a good electrical conductor. The strip 2l has at one end thereof a hole adapted to receive and be removably clamped by the stud 19. On the other end of the strip 2l is formed an offset portion 23, by bending said strip 21 twice at right angles. Secured to the off-set portion 23 (see Fig. 4) as by rivets 25 or the like is a square U-shaped piece 27, with the side arms extending at right angles to the plane of the portion 23. Mounted as by rivets 29 on the vU-shaped piece 27 is a second U-shaped piece 31, the engagementof U-pieces 31 and 27 being such that they are free to rotate upon the rivets 29. Secured by rivets 33, similar to the rivets 25, to the U-piece 31 is an extension strip 35, which may be formed of the same material from which the strip 21 is formed. The strip 35 extends both sides of the U-piece 31 with a clamping end or tongue 37 adapted to rotate against the strip 21, and a longer end 39 (see Fig. 1). The longer end 39 has a lipped end 4l, as illustrated in Figs. 1 and 3. The lip 41, while not essential, p.

is desirable to preclude abnormal wearing of the connecting wire 15.

It will be seen that by means of the above construction, a hinged joint is provided between the strip 21 and the extension strip 35. Further, the clamping end or tongue 37 of the strip i 35 is adapted, when properly tensioned, to clamp the end of the fuse wire 15 securely in position.

The assembly with the cartridges is illustrated in Fig. 1. It will be seen that the fuse link or element is clamped at the top with a stud 5, while the end wire 15 of the fuse element is brought out of the lower, open end of the tube l and clamped between the strip 21 and the extension 37 of strip 35. The strip 2l, in its normal, untensioned position, is as shown in Fig. 2. Accordingly, when it is pulled to the Fig. 1 position, and there secured by the wire 15, it places said wire 15 under tension. Further, as the tension increases, the clamping force with which the end of wire 15 is secured or trapped is also increased. This makes for a tight, rm joint, with good electrical conductivity.

The assembly illustrated in Fig. 1 is then ready for operation. If, now, the fuse blows, the portion 13 separates, thus relieving the tension on the wire 15, and at the same time permitting the strip 21 to unbend with a snap action, thus whipping the wire 15, with the fragment of the fusible element 13 .secured thereto, out of the open end of the tube l. At the same time, since the strips 21 and 35 are no longer under tension, the clamping or trapping eiect of end 37 against the strip 21 is relieved and the wire 15 is disengaged therefrom. This allows the wire 15 to fall freely and completely disengage itself from the cartridge. With a simple loosening of the stud 5, the remaining portion of the fuse element drops out through the tube 1, the cartridge is ready for the installation of a new fuse link.

A further advantage of the above construction is that the position of the strip 21, which is easily recognized at a considerable distance, indicates quickly and positively which of a number of cartridges has blown. Thus .replacement is facilitated, as it is not necessary to test several cartridges in order to determine which one requires replacement. Furthermore, only one bolt needs to be loosened in order to effect a fuse replacement.

In Figs. 5, 6 and 7 is illustrated an alternative embodiment of the invention as applied to the same type of cartridge shown in Figs. l and 2. In this embodiment a strip of spring metal 45 is provided having a normal lateral coniiguration as shown in Fig. 6. The strip 45 is provided with an opening as at 47 (Fig. .7) to receive, and be clamped by, the stud 19. At the opposite end, the strip 45 is provided with a notch 49, which leaves sidewardly positioned fingers 51. Somewhat below the upper end of the strip 45, a pair of tabs 53 are struck at right angles from said strip 45. These tabs 53 are bent to encircle, and form bearings for, a pin 55.

Swungrotatably on the pin 55 is a rigid element 57, comprising a central portion 59 having depending edges 61. The pin 55 passes through the opposite edges 61 and is bent at its outer end, to prevent it from falling out. At the lower end of the rigid piece 57 a finger 63 is struck, the finger 63 being adapted to slide into the notch 49 of the spring element 45. The edge portions 61 are extended to form fingers or tabs 65, which receive in a sliding fashion the fingers 51 of the spring portion 45.

With the device thus described secured to the cartridge by the stud 19, the wire 15 of the fuse element is bronght out of the lower end of the tube l, and is tied around the tabs or tongues 5l in such manner as to deform the spring strip 45 to the position shown in Fig. 5. The tie is such that a good electrical contact is effected between the wire 5l and the strip 45. The whole device is thus placed under tension of the bent strip 45, with electrical contacts being made to each end of the fusible element.

When, now, the fusible element blows, tension on the strip 35 is relieved and such strip immediately snaps to its relieved position illustrated in Fig. 6. In so doing, it whips the fragment of the fusible element out of the tube in position to be dropped. At the same time that the strip 45 resumes its unsprung position, the projection 63 and tabs 65 of the rigid element 59 are forced outwardly to their Fig. 6 position, thus pushing the knot portion of the wire 15 oif the tongues 51 and thus completely disengaging said wire 15 and allowing it to fall freely to the ground.

Thus, with the embodiment shown in Figs. 5 to 7, a device is provided which not only whips the fragment of the fuse element from the cartridge, but also positively and effectively disengages the electrical Contact of the end of said fuse element, and discharges it from the entire vicinity of the cartridge. The embodiment of Figs. 5 to 7 is advantageous in that it does not require the amount of space for installation that the Figs. 1 to 4 embodiment requires, and its disengaging action is more certain and positive.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. Throw-out means for a fuse cartridge comprising a resilient metallic strip adapted to be secured at one end to the side of said cartridge, means associated with said strip for securing said strip to a fuse link in said cartridge, thereby to bring the other end of said strip under tension and in proximity to the end of said cartridge, and means adapted to release said fuse link when the tension in said strip is relieved.

2. Throw-out means for a fuse cartridge comprising a resilient strip, one end of said strip being adapted for securing said strip to the side of said cartridge, an extension strip hingedly mounted on the other end of said strip, said ex- 150 tension strip having a portion adapted to clamp against said resilient strip when the end of said extension strip is tensionably brought into proximity with the end of said cartridge.

3. Throw-out means for a fuse cartridge comm prising a resilient strip, one end of said strip being adapted for securing said strip to the side of said cartridge, the other end of said strip hat"s ing at least one nger formed therewith, and a piece hingedly mounted on said resilient strip, said piece having at least one notch thereon adapted to mesh with the finger on said resilient strip when said resilient strip is tensioned 4. In combination, a tubular fuse cartridge liarum ing one clamping means at one end thereci and a second clamping means spaced from the other end thereof, a fuse link secured at one end to said first-named clamping means, and throufout means secured to the second-named clamping means, said throw-out means comprising a re= silient strip adapted tensionably to be leent to= Wards said other end of the cartridge, and means associated with said throw-out means for scour`= ing the other end of said fuse link thereto, said last-named means being adapted to release said fuse link therefrom when said resilient strip is relieved of tension.

5. In combination, a tubular fuse cartridge have ing one clamping means at one end thereof and a second clamping means spaced from the other end thereof, a fuse link secured at one end to said rst-nained clamping means, and throwout means secured to the second-named clamping means, said throw-out means comprising a re- Asilient strip adapted tensionably to be bent to@ wards said other end of the cartridge, and means associated with said throw-out means for secure ing the other end of said fuse link. thereto, said last-named means being operable secure said inse linl: only when said strip is under tension.

6. In combination, a tubular fuse cartridge hav= ing one clamping means at one end thereof and a. second clamping means spaced from the other end thereoi, a fuse link secured at one end to said rst-named clamping means, and throw-out means secured to the second-named clamping means, said throw-out means comprising a re-2 silient strip, an extension strip hingedly incunt= ed on said resilient strip, said extension strip having a region adapted to receive the other end of said fuse link and, when said extension strip` is tensionably bent toward said cartridge, to

clamp said fuse link against said resilient strip.

'7. In combination, a tubular fuse cartridge having one clamping means at one end thereof and a second clamping means spaced from the other end thereof, a fuse secured at one end to said iirst-named clamping means, and throw-out means secured to the second-named clamping means, said throw-out means comprising a resilient strip, the free end of said strip having at least one finger formed thereon, and a rigid piece hingedly mounted on said resilient strip, the iree end of said rigid piece having at least one notch therein adapted to mesh with the finger on said resilient strip when said resilient strip is tensionably iorced toward the end of said cartridge, and said meshed finger and notch being adapted to receive and tensionabh7 hold the other end oi said inse d, il inse comprising a cartridge, contacts thereon, o iuse therein, means tor lfastening one end oi said linl` to one contact, tensioning means euteriorly mounted on another contact ou said cartridge comprising a bowed spring adapted to secure the other end ci said link, said lastmamed means being adapted to eiiect direct and com "plete withdrawal the link when said tension is released upon blowing.

9, Throw-out means for a fuse cartridge hat"-= ing contacts and a flexible fuse link therein joining with one contact to close a circuit, the throwout means comprising a length of bowed spring material adapted to loe secured at one of its ends exteriorly ci the cartridge to electrically com municate with said circuit and means associated, with said spring material for securing the 4same a to said flexible fuse linl: while tensioning and bowing the spring material to position the secir ing end thereof adiacent to the end of the cartridge,`

lo, in a fuse switch oi the character described, a cartridge comprising a tube, head and foot members on the upper end lower ends ot the tube, a fusible conductor element housed within the tube and having its ends connected to said head and foot members, a fiat spring strip havs ing one end fixed on one ci the members and its opposite end arranged to forni a loop ter-1 minating in spaced relation with one end oi said tube and tensioned by said conductor element for eiecting withdrawal thereof from the tube upon 125 fusing thereof,

THEODORE B. 

